Consider the following propositions for rephrasing the fragment of sentence the south tower after burning for an hour and two minutes (l. 06-07). 
 I - the south tower after having been burning for an hour and two minutes
 II - the south tower after it was burning for an hour and two minutes
 III- the south tower after it had been burning for an hour and two minutes
If applied to the text, which ones would be correct and keep the literal meaning?